Explanation:

 * Containers and virtual machines both have similar resource allocation and allocation benefits.
 * Containers and VMs are functionally different because containers virtualise the Operating System and VMs are virtualise the hardware.
 * Containers are just processes

Explanation:

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
xdk_helloworld latest a801afaa1782 20 seconds ago 473MB
tomcat jre8 3639174793ba 3 months ago 463MB

Command to run the xdk_helloworld docker image, to listen to the port 80 and route to 8080 in the container which is the tomcat's default port 8080 at runtime.

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker run -p 80:8080 xdk_helloworld

Open http://34.204.171.134/HelloWorld/ in a browser to see the HelloWorld web is application running.

Explanation:

1. How to install Docker on Ubuntu 18.04?
2. Docker Command
3. Working with Docker Images
4. What is a dockerfile?
5. How to build a custom docker image?
6. How to run a container?
7. How to SSH into a running container?
8. How to push an image to Docker Hub?
9. How to pull an image from Docker Hub?

Explanation:

Command to get the name of the existing container

ubuntu@ip-172-31-57-91:/opt/HelloWorld$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2a41bd524e93 xdkdockerhub/xdkdockerrepo:xdk_helloworld_V1 "catalina.sh run" 5 minutes ago Up 5 minutes 0.0.0.0:80->8080/tcp sweet_hypatia

Command to get a bash shell in the container.
ubuntu@ip-172-31-57-91:/opt/HelloWorld$ docker exec -it sweet_hypatia bash

Verify with basic commands

root@2a41bd524e93:/usr/local/tomcat# ls -a

. BUILDING.txt LICENSE README.md RUNNING.txt conf lib native-jni-lib webapps
.. CONTRIBUTING.md NOTICE RELEASE-NOTES bin include logs temp work

root@2a41bd524e93:/usr/local/tomcat# ls -al
total 168
drwxr-sr-x 1 root staff 4096 May 16 00:50 .
drwxrwsr-x 1 root staff 4096 May 8 13:20 ..
-rw-r--r-- 1 root root 19539 May 4 09:22 BUILDING.txt
-rw-r--r-- 1 root root 5407 May 4 09:22 CONTRIBUTING.md
-rw-r--r-- 1 root root 57092 May 4 09:22 LICENSE
-rw-r--r-- 1 root root 1726 May 4 09:22 NOTICE
-rw-r--r-- 1 root root 3255 May 4 09:22 README.md
-rw-r--r-- 1 root root 7139 May 4 09:22 RELEASE-NOTES
-rw-r--r-- 1 root root 16262 May 4 09:22 RUNNING.txt
drwxr-xr-x 2 root root 4096 May 16 00:50 bin
drwxr-sr-x 1 root root 4096 Aug 25 11:56 conf
drwxr-sr-x 2 root staff 4096 May 16 00:50 include
drwxr-xr-x 2 root root 4096 May 16 00:49 lib
drwxrwxrwx 1 root root 4096 Aug 25 11:56 logs
drwxr-sr-x 3 root staff 4096 May 16 00:50 native-jni-lib
drwxr-xr-x 2 root root 4096 May 16 00:49 temp
drwxr-xr-x 1 root root 4096 Aug 25 11:56 webapps
drwxrwxrwx 1 root root 4096 Aug 25 11:56 work
root@2a41bd524e93:/usr/local/tomcat# exit
exit
ubuntu@ip-172-31-57-91:/opt/HelloWorld$

Explanation:

Login to the Docker Hub from the command line

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker login --username=xdkdockerhub
Password:
WARNING! Your password will be stored unencrypted in /home/ubuntu/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded

Command to pull the image from the docker hub repository.

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker pull xdkdockerhub/xdkdockerrepo:xdk_helloworld_V1
xdk_helloworld_V1: Pulling from xdkdockerhub/xdkdockerrepo
c5e155d5a1d1: Already exists
221d80d00ae9: Already exists
4250b3117dca: Already exists
d1370422ab93: Already exists
deb6b03222ca: Already exists
9cdea8d70cc3: Already exists
968505be14db: Already exists
04b5c270ac81: Already exists
301d76fcab1f: Already exists
57ca7a0b9e79: Already exists
3c1d6826d7a3: Already exists
24ab01b57aed: Pull complete
Digest: sha256:47252a9c0bf7f4fe9a024ab69a7d709db3d27d409cbc66dfcddcfc1a20a04cda
Status: Downloaded newer image for xdkdockerhub/xdkdockerrepo:xdk_helloworld_V1

Verify the image.

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
xdkdockerhub/xdkdockerrepo xdk_helloworld_V1 a801afaa1782 39 minutes ago 473MB
tomcat jre8 3639174793ba 3 months ago 463MB

Command to run the xdk_helloworld docker image and change the container to listen to port 80 instead of tomcat's default port 8080 at runtime.

ubuntu@ip-172-31-59-138:/opt/HelloWorld$ docker run -p 80:8080 xdkdockerhub/xdkdockerrepo:xdk_helloworld_V1

Open http://34.204.171.134/HelloWorld/ in a browser to see the HelloWorld web is application running.